1. Field of the Invention
The invention is generally directed to a fuel cell installation with a gas generation system, to produce a hydrogen-containing gas, and a fuel cell system.
2. Description of the Related Art
DE 197 55 116 C1 describes a fuel cell system, in which the air supply system for a fuel cell includes a compressor that obtains at least part of the required energy from an expander. The expander is driven by the hot exhaust gases of a burner, in particular a catalytic burner. The burner burns exhaust gases from the anode chamber and the cathode chamber of the fuel cell, which contain oxygen and residual amounts of fuel that have not been converted in the fuel cell.
In order to compensate for higher power requirements by the compressor, it is possible to increase the output of the expander by providing methanol as an additional fuel to the burner. As a result, the expander is able to provide more power for the compressor. However, this design has the disadvantage that its response to strongly varying dynamic power requirements by the compressor is not fast enough. Consequently, the power demand is often not met. For this reason, the compressor must be equipped with a further driving element, for example an electric motor, in order to ensure reliable operation in all situations.
Also known are fuel cell systems, which utilize the energy produced by a catalytic burner to supply thermal energy to a gas generation system or to individual components of a gas generation system. This offers definite advantages with respect to the overall system efficiency. However, this direct thermal coupling between the fuel cell system and a gas generation system also has some disadvantages. For example, it complicates the operation of the overall installation during start-up since the exhaust gas that is required for heating purposes originates in the component that is usually arranged in the most downstream position. Accordingly, all other components must first be heated and operational.
In addition, the direct thermal coupling makes the overall installation more susceptible to faults, since performance problems in one part of the system may automatically cause problems in other parts of the installation, which otherwise could be prevented. For example, if the catalytic burner degrades, the required temperature—for example, for reforming or a similar process—can no longer be obtained. This disturbs the entire operating sequence, even though the other parts of the installation still operate without problems. As a result, the entire installation can be affected, since operation of the gas generation system and the fuel cell system are directly coordinated and linked with each other.
Accordingly, there remains a need for improved fuel cell installations that overcome the disadvantages set forth above. The present invention fulfills one or more of these needs, and provides further related advantages.